Apparatus for forming or dressing the operative surface of grinding wheels



April 1941- J. E. WAINWRIGHT 2.237.977

APPARATUS FOR FORMTNG OR DRESSING THE OPERATIVE SURFACE OF GRINDING WHEELS Filed Sept. 5, 1940 2 sheeizs-Sheet 1 a FIG. L d I m n d l d h h I I I wmmwwd FIG.

April 8, 1941. J E wm w H 21,237,977

APPARATUS FOR FORMING OR DRESSING THE OPERATIVE SURFACE OF GRINDING WHEELS Filed Sept. 5, 1940 2 Sheets-Sheet 2 Patented Apr. 8, 1941 APPARATUS FOR FORMING OR DRESSING THE OPERATIVE SURFACE OF GRINDING WHEELS John Ernest Wainwright, Coventry, England Application September 3, 1940, Serial N 0. 355,248 In Great Britain December 23, 1938 5 Claims.

This invention relates to an improved apparatus for forming or dressing the operative surface of grinding Wheels for use more particularly in producing or finishing screw threads of all V-forms.

The improved apparatus is distinguished from existing methods in that it does not involve the use of a master or former nor does it depend upon the use of a rotating cam, lead screw or other accurately Worked elements.

According to the present invention the movement of the forming or dressing tool or tools is obtained by a combination of polar and rectilinear motions and one or more inclined sur faces, the polar motion determining the depth component of the form required and the rectilinear motion in co-operation with the inclined surface determining the angle and effective dimension of the said form.

The relative and respective extents of the polar and rectilinear motions may be varied at will as also the angularity of the inclined surface or surfaces.

The apparatus employed in carrying out the improved method above described is simple, compact and capable of easy manipulation and ad- J'ustment.

In the accompanying drawings, I

Figures 1 and 2 are side and end elevations respectively of a wheel dressing attachment constructed according to the invention.

Figure 3 is a view similar to Figure 1 showing a slightly modified form of the wheel dressing attachment.

Referring more particularly to the construction shown in Figures 1 and 2 of the drawings a represents part of a grinding wheel, and b the grinding machine bed or a table thereon. The dressing tools 0, c are carried by a member or carriage d arranged for rotational and sliding movements in a fixed base member e which is adjustably mounted on the bed or table 22 by means of bolts 1. The member or carriage d is in the form of a sleeve loosely mounted on a pin 0 carried between lugs h on the member e and is provided at one side with a radially projecting arm (1 in the free end of which the wheel-forming tools 0, c are mounted. At the opposite side, the member d is provided or formed with a pair of radially projecting arms or lugs d (1 in the free end of each of which are mounted two adjustable stops. One pair 2', i of these adjustable stops serve to limit the rotational movement in one direction of the member d, for which purpose they are adapted to bear upon the fixed member manner.

e. A stop 7' on the member at co-operating with an adjustable stop 7c in the fixed member 8 serves to limit the rotational movement in the other direction of the said member (2. The other pair Z, Z of adjustable stops in the arms or lugs (1 d are axially adjustable and co-operate with a swinging guide bar m pivotally mounted at n in the fixed member e to control the compound angular and sliding movement of the member (I.

The distance between the operative portions of the tools 0 and the rotational axis of the member d may be equal to, or in any suitable ratio to, the distance between said axis and the contacting portions of the axially adjustable stops 1, 1.

Movement of the bar m about its pivot 11 is limited by stops 0, 0 adjustable in a curved slot p in the top plate of the fixed member 6. The bar m can be locked in any predetermined position by means of a locking screw q working in the curved slot p.

The wheel-forming tools 0, c are spaced apart so that when one of the adjustable stops 1, l is in contact with the bar m, one of said tools will be in its operative position on the grinding wheel, and when the other of said adjustable stops is in contact with the bar, the second tool will be in operation on the grinding wheel. This arrangement also provides that when one tool is in operation on the grinding wheel the other is clear.

The apparatus is arranged on the bed or table b with the axis of the movable member d parallel with the axis of the grinding wheel and with the dressing tools at equal distances from each side of the latter and the member (2 at an inoperative position with the adjustable stops 1, Z equidistant from the bar m.

In setting the apparatus for forming or dressing a single rib grinding wheel for producing screw threads of the Whitworth type, the movable member d is rotated so that the stops :i and is contact with each other. Provision may be made for it to be normally held in this position by means of a spring or in any other convenient A gauge block or feeler of, or proportional to, the depth dimension of the required form is then inserted between the two adjustable stops 1', i and their contact faces on the fixed member e, and the said stops adjusted to it. This determines the angular movement of the member at and of the dressing tools 0, c. The axially adjustable stops 1, l which co-operate with the bar m to controlthe compound movement of the member dare next adjusted according to the distance between the dressing tools and the required effective dimension of the form on the grinding wheel. The stops 0, o are adjusted according to the angle of the form to be produced, and the :bar m is locked in position in contact with one of said stops and is inclined at an angle which depends on the angle of the side flanks of the form to be produced on the grinding wheel.

In using the apparatus, the movable member (1 is given a combined sliding and rotational movement on its supporting pin g in the fixed member e during which movement one of the stops 1 contacts with the inclined face of the bar m. The effect produced is to cause one of the tools-to dress one side of the wheel. The bar m is then readjusted and locked in contact with the other of the stops 0, .0, and the process repeated with the other axially adjustable stop 1 contacting with the bar m. This causes the other tool to dress the other side of the wheel. The co-action of the stops 1, l and the inclined surfaces of the bar m,

causing the tools to produce the required V-form on the wheel.

In the modification shown in Figure 3, the construction and method of operation is similar to the foregoing, except that the swinging bar m is not locked in position but is automatic in action. For this purpose the bar m is pivoted on the fixed member 6 at a point below the cooperating stops Z, Z and is free to swing between adjustable stops 0 If the member 41. is now given a combined reciprocating and rotational movement, the stops 1, I will swing the bar about its pivot first in one direction and then in the other between the limiting stops 0 0 The effect produced is to cause the tools 0, c alternately to dress opposite sides of the wheel, the co-action between the stops Z, Z and the swinging bar causing the tools to produce the required V-form on the wheel.

The cross-sectional shape and dimensions of the form produced in both cases can be varied at will by appropriate adjustment of the various stops.

Alternatively, a single tool and/or control stop can be used for dressing both sides of the wheel, the tool being swung through an angle of 180. A double swing bar can be employed with either method.

The tools may, if desired, be formed to produce a form on the wheel which will give a radiussed crest on the screw thread.

The improved device can be used for giving the wheel a primary basic form for subsequent finishing by a crushing operation, or in certain cases, for producing a form which can be employed for production purposes.

I claim:

1. Apparatus for forming and dressing the operative surfaces of grinding wheels comprising a base member adapted for adjustable attachment to the bed of the grinding machine, a pivot pin carried by said base member, a sleeve mount ed for angular and axial movements on said pin, a radially projecting arm on said sleeve, a pair of dressing tools carried by said arm, a bar pivoted in said base member, a pair of adjustable stops carried by said sleeve and arranged one at each side of said bar, and adjustable stops for limiting the angular motion of said sleeve.

2. Apparatus for forming and dressing the operative surfaces of grinding wheels comprising a base member adapted for adjustable attachment to a grinding machine and carrying a pin arranged with its axis parallel with the axis of the grinding wheel, a sleeve member loosely mounted on said pin and carrying a dressing tool for each side of said wheel, a bar having a surface inclined to the axis of said pin and a pair of adjustable stops on said sleeve member arranged one at each side of said bar and adapted, when the sleeve member is moved axially on said pin, to co-operate with the inclined surface of said bar to give the sleeve member a simultaneous predetermined angular motion about said pin.

3. Apparatus for forming and dressing the operative surfaces of grinding wheels comprising a base member, a sleeve member having a combined angular and axial movement therein, a pair of dressing tools carried by said sleeve member, a bar pivotally mounted in said base member, a pair of stops carried by said sleeve member and adapted to co-operate alternatively with opposite sides of said bar.

4. Apparatus for forming and dressing the operative surfaces of grinding wheels, comprising a base member, a pin carried thereby, a sleeve member movable axially on said pin and carrying a pair of dressing tools, one for each side of the grinding wheel, a bar pivoted in said base member and free to swing in a plane parallel with the axis of said pin, and a pair of stops on said sleeve member, said stops being arranged to contact with opposite edges of said bar during axial movement of said sleeve member for the purpose of imparting a predetermined angular motion to said sleeve member about said pin.

5. Apparatus for forming and dressing the operative surfaces of grinding wheels comprising a base member, a carriage mounted on said base member for pivotal movement about a fixed axis and reciprocation in the direction of said axis, a pair of relatively axially spaced dressing tools carried by said carriage for alternate engagement with opposite sides of a grinding wheel during reciprocation of said carriage, and a guide bar mounted on said base member and formed with oppositely disposed guide surfaces, in combination with stop means carried by said carriage and arranged to alternately engage and move along the opposed guide surfaces of said bar to control the pivotal movement of said carriage and the dressing tools carried thereby.

JOHN ERNEST WAINWRIGHT. 

